German Auslegeschrift No. 2 901 943 describes a method of producing wood pulp in which wood is hot-ground on a grindstone utilising a hot liquid having a boiling point in excess of 100.degree. C. at atmospheric pressure. The method is highly uneconomical and has a high energy consumption.
German Offenlegunngsschrift No. 1 811 187 describes another method and a device whereby wooden slats are fed to a rotating grindstone from both sides. Such a grinder is more efficient because twice the amount of wood pulp is produced.
In addition, so-called continuous grinders for producing wood pulp are known and one such arrangement is disclosed in German Auslegeschrift No. 1 461 009 which permit amounts of wood to be continuously supplied to a rotating grindstone through a pressure-actuated chute. The object of such a grinder is to standardise the downward pressure so that wood fibres of uniform size are produced.